This application requests support for the program of the Division of Chemical Toxicology of the American Chemical Society (ACS) at its 248th National Meeting and Exposition in San Francisco, CA from August 10, 2014 to August 14, 2013. A unique feature of this ACS meeting is the broad theme of the national meeting, Chemistry and Global Stewardship , which aligns highlighted events across the meeting programs of all ACS divisions. The mission of the ACS Division of Chemical Toxicology is to promote the understanding of chemical mechanisms contributing to disease processes and the toxicity of environmental agents, biomaterials, drugs and endogenous chemicals. The Division integrates work in chemistry, chemical biology, structural biology, toxicology, environmental health sciences and disease mechanisms. Three interrelated symposia are planned around the central theme Mechanisms and Biomarkers of Environmental Stress and include invited oral presentations delivered by a diverse group of leading established and emerging scientists. The three symposia for which support is requested have particularly strong relevance to the mission of the NIEHS. The first is entitled Biomarkers for environmental exposure and highlights the recent advances in the discovery of biomarkers for monitoring the exposure to various environmental toxicants. The second is entitled Biomarkers of oxidative stress and focuses on recent developments about the use of LC-MS/MS for monitoring the oxidation products of protein and DNA. The third symposium session is entitled Mechanisms of base excision repair and focuses on mechanisms of DNA base excision repair, a very important DNA repair pathway for removing many single-nucleobase DNA lesions induced by environmental carcinogens. A proffered paper session and a Young Investigators Symposium offer opportunities for young scientists in training to present their primary contributions and receive critical feedback from senior experts. Other highlights are a keynote lecture by Dr. Martyn Smith (University of California Berkeley) and two high-profile award symposia (the Founders Award and the Chemical Research in Toxicology Young Investigator Award). These sessions (supported by non-federal funds) will further enhance a strong overall program and provide diverse participants an outstanding representation of current work in the chemistry and biology of environmental exposure and disease.